toyota h engine oil pump

Alec

A pump creates flow, pressure is the sum of resistance, so meaning the resistance to the flow will create pressure. bigends, littleends, cam shaft bushes anywhere oil can get out.

Sorry

Richard

Assuming it's a gear type pump (most of them are, AFAIK), these can and do wear, and yes they are re-buildable..

To remove, it's usually as simple as removing the sump and removing a few bolts ;-)

The first thing I would check (always start with the simple things) is the relief valve.. could be as simple as a 'tired' or broken spring.. Will do no harm to give it a clean anyway;-) ...

As stated above, excessive bearing clearance will lower oil pressure, but if she ain't rattlin' I wouldn't be too concerned about that (yet)...

Have you tried a heavier viscosity oil?

:)

Hi Alec L if its got an electric oil gauge I would tmperarily fit a mechanical gauge & check first, & make sure oil gallery to gauge fitting isnt blocked with sluge. Daryl

As you probably know the the H & 2H motors have two oil pressure senders, one for the gauge and one for the EDIC (Electronic Diesel Injection Control) system which is Toyota's way of saying there is an electric motor to move the rack from stop, start and run positions as you turn the ignition key. This second oil pressure sensor detects engine oil pressure and in the event that there isn't any it shuts the engine down to prevent damage. This is because these motors and many others with inline injection pumps will quite happily run in either direction, it is quite funny when it happens, huge quantities of black smoke out the aircleaner which of course is nicely coated with soot on the inside of the element. The problem is that the oil pump is running backwards, sucking oil from the engine and blowing it into the sump, not good for oil pressure!
First step would be to get a proper calibrated gauge to see what the oil pressure actually is.
If it is down check the oil pressure relief valve as they do gum up, get weak or broken springs etc.
I would be getting a diesel mechanic to check it properly as they have the knowledge and the experience to ascertain what the problem is.

Alec,,,The oil pump on the H engine is located on the front of the crank shaft behind the timing cover. You can easyly check the relief valve and spring as there is a big nut 1 inch from memory on the right hand side behind the front crank pully. Undo the nut with a ring spanner and then remove the spring and slide, there is a steel ball behind that. Check the tension of the spring, there is a nominal length but can't remember off hand what it is. I would replace this spring with a new one as they are not expensive and should still be available. They did have a habit of loosing tension over time and may just fix your problem. Also check the seat behind the ball as this can be worn and leaking but if so would need the oil pump removed. To do that it's radiator out front pully off, timing cover off then oil pump. Quite likely the spring though and if the vacuum in your brakes has not been to good lately this would also confirm it and that is not a joke. Hope this helps you out.

Alec,
I had the H engine too. The oil filter is a cartridge type and does not have any type of anti-flow back valve. My engine too did this, the oil drained out of the filter and you had to start the engine twice before the pressure built up and it didn't cut out. I didn't solve the problem on mine so sorry I can't help. I thought on mine it would be some sort of check valve or non-return valve as others have suggested here. If you can work out where they are and which one has worn - I think you should solve the problem. Good luck.
As an aside, it is funny listening to people complaining about the 'gutless' 1HZ - they should try driving the H diesel :)

thanks all for the advice, a big help ;)